Simple term, meant to be refered to the sort of devianart or autistic people that draw for years and years and seem to been unable to improve to even the basic level, hence the permabeg, someone incapable of activating the most basic of artskills despite all the efforts. Later on as it started to be an form of insult from the lesser users of the board the meaning itself lost it's value.
Permabegness now has no actual meaning, is something close to IC's nigger or any other useless slur or insult without any actual strong context like fucker or Incel, is meant as more an form of insult from people that have nothing to say but still wish to express their contempt or anger, imagine the closest thing a human will ever do from simply barking like any wild animal or dog would do.
You can also atributte the change to the change of the maning of the world /beg/ and what it inplied since the /beg/ threads have been invaded from people that before were outside the level an d the skill level to be a /beg/ changed wildly, imagine a country with no middle-class, only rich and poor people, this is /ic/ now and no balance between who is skilled and unskilled, advantageous if are smart enough to use it but disadvantageous for people without the abstract thinking to use
it. Well, happens, new people come, don't bother to learn things and use words wrong, things change as newcommers appear and do the same. Stupidity, mostly, the biggest cancer that still afflicts humanity as a whole.
The implications on the website as a whole and what it means from each board culture are more interesting to me, but english based imageboards are more an extension of social media and not anti-culture or a complete separated would compared with foreign counterparts, so it's not as interest as it could be, just curious I suppose.